The flexible OLED (Organic Light-Emitting Diode) element generally employs the thin film package, in which the package structure comprises the inorganic thin film layer. The inorganic thin film layer is generally compact, and the thin film stress exists in the deposition process so that the bendability of the inorganic thin film layer is poor. When the flexible OLED is curled and folded, the inorganic thin film layer can easily have crack and peeling; once the crack occurs, crack pattern can be quickly spread, and ultimately leads to the large area failure of the flexible OLED element.